docs: def _get_pika_properties(properties_in):
          """Return a :class:`pika.spec.BasicProperties` object for a
          :class:`rejected.data.Properties` object.
  
          :param dict properties_in: Properties to convert
          :rtype: :class:`pika.spec.BasicProperties`
  
          """
          properties = pika.BasicProperties()
          for key in properties_in or {}:
              if properties_in.get(key) is not None:
                  setattr(properties, key, properties_in.get(key))
          return properties